Revised Abstract: "Silencing of Apoptotic Pathways in TCC by DNA Methylation", is led by Dr. Peter A. Jones and represents the first systematic study investigating the role of epigenetic mechanisms, DNA methylation, and gene silencing in human tumors. The project leader will utilize state-of-the-art genome scanning and quantitative techniques to study methylation changes occurring during bladder carcinogenesis. In the previous review, this project was judged to be of high scientific merit and essentially no significant deficiencies were noted, hence no major alterations in the project have been made. In Specific Aim 1, genes specifically involved in apoptotic pathways in transitional cell carcinomas (TCC) of different grades and stages will be evaluated. The approach of concentrating on a single pathway in methylation and incorporation of environmental factors is innovative. By assessing the timing, magnitude, and potential significance of tumor related DNA methylation during malignant transformation, a better understanding of the cause and effect relationship of these genome-wide alterations with tumor progression will emerge. The goals of this specific aim are well integrated the efforts in Project 3, which will evaluate expression levels of the proteins of these genes. In Specific Aim 2, the methylation status of these same genes will be evaluated in a set of human tumors obtained from the SEER program, which contains significant epidemiologic data. This information will be utilized to explore the relationship between cigarette smoking and DNA methylation status. Specific Aim 2 is also very well integrated with Project 2, in that Project 2 will evaluate the expression of the proteins encoded by the genes evaluated for promoter methylation in Project 1 on the same set of patients. Specific Aim 3 represents a mechanistic approach to evaluate the affect of methylation status on cisplatin-induced apoptosis in different cellular environments. This project is highly likely to be successful in providing new biomarkers for bladder cancer detection and diagnosis and may also impact the clinical management of these tumors. This highly meritorious project received an average merit rating of 1.5 in the previous review, and received the same score (1.5) in the current submission.